Consumer Redressal

I have purchased a Samsung E5 phone from R.G.Networks(South City Mall Kolkata) on 15.04.2015 and within 20 days the phone was found defective. Now samsung servie centre or the dealer is not helping me replace the phone and forcing me to get the handset repaired. Spoke to the service head Rajesh singh, who is equally uncooperative and rude. Since the phone is found defective within three weeks of purchase i want replacement of the phone..